Abstract

Catchability coefficients (q) as derived from the relationship between indices of catch per unit of effort (CPUE) and average exploitable biomass were positively correlated with indices of technological changes in the fleets fishing for the major groundfish stocks off the east coast of Canada. There was no evidence of correlation of q with abundance indices from research-vessel survey data. It was therefore concluded that the increase in q observed in the mid-1970s was a result of improved technology by the vessels involved. This was further substantiated by the relative change in the proportion of the total effort expended by the large vessels in the fleet over the period examined and the corresponding larger CPUE of these vessels relative to the remainder of the fleet.